Internal combustion engine cold-start systems



J. P. CLARK Aug. 29, 1967 INTERNAL COMBUSTION ENGINE COLD-START SYSTEMS 2 Sheets-Sheet 1 Filed June 21, 1965 Inventor Irma; fizf/v'c/f C/arfi" BY Attorney Aug. 29, 1967 J. P. CLARK 3,333,226

INTERNAL COMBUSTION ENGINE COLD-START SYSTEMS Filed June 21, 1965 2 Sheets-Sheet 2.

Inventor QXW Attorney United States Patent 3,338,226 INTERNAL COMBUSTION ENGINE COLD-START SYSTEMS James Patrick Clark, Luton, England, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed June 21, 1965, Ser. No. 465,565 Claims priority, application Great Britain, June 22, 1964, 25,805/ 64 4 Claims. (Cl. 123-179) ABSTRACT OF THE DISCLOSURE A cold-start system for internal combustion engines and particularly diesel engines, including a fuel tank filled by return flow from the injectors and from which fuel is supplied to an igniter device in the engine intake manifold during electrical actuation of the igniter device through a manually-actuated switch. The switch is combined with a fuel tank vent valve such that closing of the switch opens the vent valve, permitting flow of fuel from the tank to the intake manifold as controlled by a valve in the igniter, while opening the switch closes the vent valve, stopping the free flow of fuel from the tankto the manifold.

This invention relates to cold-start systems for internal combustion engines and in particular to cold-start systems for compression ignition internal combustion engines in which an igniter device is adapted to ignite in the engine intake manifold a small quantity of fuel supplied from a gravity supply tank, so as to pre-heat the air for combustion.

In a known igniter device a tubular valve body is carried in a holder which is screwed into the engine air intake manifold and is surrounded'by a heater coil, an

extension of which forms an igniter coil. The valve body carries a central rod or needle the end of which holds a ball valve in position against its seat. Fuel is adapted to be admitted to the igniter by way of the ball valve which is normally held on its seat by the end of the central rod. When current is supplied to the coil the latter is heated and the resultant expansion of the tubular valve body causes the central rod to be moved sufficiently to allow the ball valve to lift and allow the passage of fuel to the heater coil which vaporizes the fuel and ignites the mixture of vaporized fuel and air in the engine intake manifold. In a known cold-start system employing such an igniter device fuel is adapted to be supplied to the igniter device from a gravity supply tank which is maintained full by the overspill from the engine fuel injection pump, the excess fuel supplied to the gravity supply tank passing by way of a further pipe from the gravity supply tank back to the main engine fuel tank.

A difi'iculty which arises in such a cold-start system is that the delivery of fuel from the gravity supply tank to the igniter device is sometimes found to be restricted, apparently by the development of a small degree of vacuum in the gravity supply tank. Attempts to solve this problem by the provision of a light spring loaded valve arranged so as to relieve any vacuum in the gravity supply tank have not been successful as it is found that at low engine speeds the vibration of the engine is sufiicient to unseat the lightly loaded valve and permit fuel to be discharged from the gravity supply tank into the intake manifold when it is not required.

According to the invention in such a cold-start system the delivery of fuel to the igniter from the gravity supply tank is controlled by a valve by which the top of the tank can be vented to atmosphere, and the opening and closing of the valve is arranged to be co-ordinated with the closing and opening of an electric circuit to the igniter.

igniter returns the valve member to the position in which it closes the valve. The vent valve conveniently comprises a plunger having an annular seal member on its end face, the plunger forming part of a reciprocatory electric switch member, axial movement of the plunger in the direction to close the switch contacts to complete the igniter circuit disengaging the annular seal member from a seat at the end of a vent pipe connected to the top of the supply tank, movement of the plunger in the opposite direction seating the seal member on said seat.

The scope of the invention is defined by the appended claims; and the invention and the method by which it is to be performed are hereinafter particularly described with reference to the accompanying drawings in which:

FIGURE 1 is an elevation of part of an internal combustion engine with a cold-start system according to the invention, showing diagrammatically the electrical connections therefor;

FIGURE 2 is a part sectional elevation, to an enlarged scale, of part of a switch and valve assembly shown in FIGURE 1;

FIGURE 3 is a detail of FIGURE 2, showing the valve in its open position; and

FIGURE 4 is a sectional elevation of the igniter device shown in FIGURE 1.

In a preferred embodiment of the invention a small gravity supply fuel tank 1 is connected to the fuel injection system of a compression ignition engine 2 so as to be maintained full, the tank 1 having an inlet 3 to which fuel is supplied by a pipe 4 from the fuel injection pump overspill of the engine. The excess fuel supplied to the tank 1 passes by way of a further pipe 5 back to the main engine fuel supply tank (not shown).

A vent pipe 6 is connected :to the top of the small supply tank 1 and the free end of the vent pipe 6 is connected to one end 7 of a tubular valve housing 8 which is open to atmosphere at its other end 9'. The housing 8 is secured to a switch 9 of a known kind, operable by a reciprocatory switch spindle 10, the end of the latter having formed integral therewith a plunger 11 which extends into the tubular valve housing 8. The end of the plunger 11 carries a head 12 on which is secured a seal ring 14 adapted to engage an annular seat 15 in the valve housing 8 so that when the seal ring 14 engages the seat 15 the housing 8 is sealed from atmosphere and when the seal ring 14 is disengaged from the seat 15 the valve housing 8 is opened to atmosphere at its end 9'.

The reciprocatory spindle 10 of the switch 9 is mounted for axial movement in a switch housing 16, :the end of the spindle opposite the plunger 11 carrying a manually operable knob 17 and an intermediate portion of the spindle 10 carrying a contact plate 18 which, in one axial position of the spindle 10 engages and bridges a pair of contacts 19, 20 respectively connected to external terminals 21, 22, and in the other axial position is disengaged from said contacts. The spindle 10 is normally biased by a spring (not shown) to the open position of theswitch.

The terminals 21, 22 are adapted to be connected in series with the heater element of an igniter 24, terminal 21 being connected to'one side of a supply battery and terminal 22 to a terminal 25 which is connected to one end of the igniter heater coil 26 (FIGURE 4) the other end of which is connected to earth by way of the igniter which is secured in the intake manifold 30 of the engine 2.

The igniter 24 is of known kind and has a tubular valve body 31 carried in a holder 32 which is screwed into the intake manifold 30 and is surrounded by the heater coil 26 and integral extension 33 of which forms an igniter coil. The valve body 31 carries a central rod 34 the end of which holds a valve ball 35 on its seat 36. As shown in FIGURE 1, the tubular valve body 31 is connected to one end of a pipe 37 the other end of which is in communication with the base of the fuel supply tank 1.

An open perforate shield 38 extends about the igniter coil.

In the operation of the igniter 24, the application of current to the heater coil 26 heats the tubular valve body 31, which expands. The end of the rod 34 is thus rnoved sufficiently to allow the valve ball 35 to lift and admit fuel which flows along the heated tubular valve body 31 and is vaporized. As the fuel vapour reaches the open coils of the ignition coil 33, which reach ignition temperature, it is mixed with some of the air drawn into the intake manifold 30 when the engine 2 is started, and ignites, thereby pre-heating the combustion air for the engine.

In the operation of the cold-start system according to the invention the knob 17 is manually depressed to move the spindle axially and engage the contact plate 18 with the contacts 19, 20 and thereby energise the igniter 24 for operation as described in the foregoing paragraph. At the same time, the axial movement of the spindle 10 and the plunger 11 integral therewith unseats the seal ring 14 on the head 12 from the seat 15 in the valve housing 8 and permits air to enter the vent pipe 6 and pass into the top of the supply tank 1, thus ensuring the free flow of fuel under gravity to the igniter 24, but the fuel will not be delivered to the igniter device 24 until the heat from the heater coil 26 of the igniter has caused the valve ball 35 in the igniter to be unseated. The fuel then passes freely by way of the outlet pipe 37 from the supply tank 1 to the igniter 24 and is vaporized and ignited by contact with the heater and igniter coils 26, 33 of the igniter 24. The cold-start system is normally operated for a period of about 15 seconds :before the engine starter motor is operated and as soon as the engine fires the use of the cold-start device can be discontinued. Thus when the cold-start switch knob 17 is released the return movement of the reciprocatory switch spindle 10, under spring action, causes the plunger 11 to be moved so that the seal ring 14 carried thereon engages the annular seat 15 in :the valve housing 8 and seals the housing from atmosphere, thus preventing further delivery of fuel from the supply tank 1 to the igniter 24.

I claim:

1. In a cold-start system for an internal combustion engine having an intake manifold, an electrical igniter in the intake manifold, a gravity supply tank connected with and adapted to supply fuel to the intake manifold, means to energize the igniter to vaporize and ignite fuel supplied to the intake manifold whereby to preheat air for combustion in the engine, a vent valve connected with the top of the supply tank to permit the venting of the tank to atmosphere and means to coordinate the opening and closing of said vent valve with operation of said igniter energizing means to assure the delivery of fuel from said supply tank to said intake manifold during the energizing of said igniter, said igniter energizing means comprising an electric circut controlled by a manually operable switch, said switch including a reciprocatory member operatively connected with said vent valve such that operation of said switch to complete the electric circuit to said igniter opens said vent valve, thereby permitting air to enter the top of said supply tank and ensuring the delivery of fuel to the igniter, and operation of said switch to break said electric circuit closessaid vent valve, said vent valve comprising a valve housing connected with the top of said supply tank, an annular seat in said housing, a plunger forming a part of said switch, said plunger having an end face on which is carried an annular seal adapted to seat against said annular seat to prevent flow through said housing, movement of said plunger in a direction to close said switch disengaging said seal from said annular seat and movement of said plunger in the opposite direction opening said switch and. seating said seal on said annular seat.

2. The system of claim 1 and further including a main fuel tank and means for continuously supplying fuel from said main fuel tank to said gravity supply tank. I

3. The system of claim 2 wherein said engine includes a fuel injection pump adapted to receive fuel from said main fuel tank and having a fuel overspill line and said tank fuel supplying means includes an inlet connected with said injection pump overspill line to receive fuel therefrom.

4. The system of claim 3 and further including excess fuel return means associated with said gravity supply tank and including an outlet pipe to return excess fuel from said gravity supply tank to said main fuel tank.

References Cited UNITED STATES PATENTS 1,691,128 11/1928 Redmond 123179 X 2,993,487 5/ 1961 Konrad 123-122 X FOREIGN PATENTS 933,331 8/1963 Great Britain. 946,156 1/ 1964 Great Britain.

CARLTON R. CROYLE, Primary Examiner.

RALPH D. BLAKESLEE, Examiner. 

1. IN A COLD-START SYSTEM FOR AN INTERNAL COMBUSTION ENGINE HAVING A INTAKE MANIFOLD, AN ELECTRICAL IGNITER IN THE INTAKE MANIFOLD, A GRAVITY SUPPLY TANK CONNECTED WITH AND ADAPTED TO SUPPLY FUEL TO THE INTAKE MANIFOLD, MEANS TO ENERGIZE THE IGNITER TO VAPORIZE AND IGNITE FUEL SUPPLIED TO THE INTAKE MANIFOLD WHEREBY TO PREHEAT AIR FOR COMBUSTION IN THE ENGINE, A VENT VALVE CONNECTED WITH THE TOP OF THE SUPPLY TANK TO PERMIT THE VENTING OF THE TANK TO ATMOSPHERE AND MEANS TO COORDINATE THE OPENING AND CLOSING OF SAID VENT VALVE WITH OPERATION OF SAID IGNITER ENERGIZING MEANS TO ASURE THE DELIVERY OF FUEL FROM SAID SUPPLY TANK TO SAID INTAKE MANIFOLD DURING THE ENERGIZING OF SAID IGNITER, SAID IGNITER ENERGIZING MEANS COMPRISING AN ELECTRIC CIRCUIT CONTROLLED BY A MANUALLY OPERABLE SWITCH, SAID SWITCH INCLUDING A RECIPROCATORY MEMBER OPERATIVELY CONNECTED WITH SAID VENT VALVE SUCH THAT OPERATION OF SAID SWITCH TO COMPLETE THE ELECTRIC CIR- 